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7d1fde7438
The anti-entropy feature has never actually worked. We've been
talking about removing it or replacing it for ages, but haven't
had a concrete motivation.
But the anti-entropy interface is the sole user of several components
of the Tx interface, and now that we're trying to replace that
interface, being able to drop those components has some appeal, so
let's remove the one thing that used them, in the hopes that this
will simplify life.
This also lets us drop ForEach and ForEachRange, which were
barely used at all. The one surviving usage (CSV export) can be
handled by using the container iterator we already have, and
making ContainerCallback exported so we can use it to just call
things for every bit.
(cherry picked from commit fff9ddc1f5)
120 lines
3 KiB
Go
120 lines
3 KiB
Go
// Copyright 2022 Molecula Corp. (DBA FeatureBase).
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// SPDX-License-Identifier: Apache-2.0
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package pilosa
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import (
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"fmt"
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"github.com/featurebasedb/featurebase/v3/roaring"
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)
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// iterator is an interface for looping over row/column pairs.
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type iterator interface {
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Seek(rowID, columnID uint64)
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Next() (rowID, columnID uint64, eof bool)
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}
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// bufIterator wraps an iterator to provide the ability to unread values.
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type bufIterator struct {
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buf struct {
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rowID uint64
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columnID uint64
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eof bool
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full bool
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}
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itr iterator
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}
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// newBufIterator returns a buffered iterator that wraps itr.
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func newBufIterator(itr iterator) *bufIterator {
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return &bufIterator{itr: itr}
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}
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// Seek moves to the first pair equal to or greater than pseek/bseek.
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func (itr *bufIterator) Seek(rowID, columnID uint64) {
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itr.buf.full = false
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itr.itr.Seek(rowID, columnID)
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}
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// Next returns the next pair in the row.
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// If a value has been buffered then it is returned and the buffer is cleared.
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func (itr *bufIterator) Next() (rowID, columnID uint64, eof bool) {
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if itr.buf.full {
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itr.buf.full = false
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return itr.buf.rowID, itr.buf.columnID, itr.buf.eof
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}
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// Read values onto buffer in case of unread.
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itr.buf.rowID, itr.buf.columnID, itr.buf.eof = itr.itr.Next()
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return itr.buf.rowID, itr.buf.columnID, itr.buf.eof
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}
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// Peek reads the next value but leaves it on the buffer.
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func (itr *bufIterator) Peek() (rowID, columnID uint64, eof bool) {
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rowID, columnID, eof = itr.Next()
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itr.Unread()
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return
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}
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// Unread pushes previous pair on to the buffer.
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// Panics if the buffer is already full.
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func (itr *bufIterator) Unread() {
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if itr.buf.full {
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panic("pilosa.BufIterator: buffer full")
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}
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itr.buf.full = true
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}
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// sliceIterator iterates over a pair of row/column ID slices.
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type sliceIterator struct {
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rowIDs []uint64
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columnIDs []uint64
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i, n int
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}
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// newSliceIterator returns an iterator to iterate over a set of row/column ID pairs.
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// Both slices MUST have an equal length. Otherwise the function will panic.
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func newSliceIterator(rowIDs, columnIDs []uint64) *sliceIterator {
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if len(columnIDs) != len(rowIDs) {
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panic(fmt.Sprintf("pilosa.SliceIterator: pair length mismatch: %d != %d", len(rowIDs), len(columnIDs)))
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}
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return &sliceIterator{
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rowIDs: rowIDs,
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columnIDs: columnIDs,
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n: len(rowIDs),
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}
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}
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// Seek moves the cursor to a given pair.
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// If the pair is not found, the iterator seeks to the next pair.
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func (itr *sliceIterator) Seek(bseek, pseek uint64) {
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for i := 0; i < itr.n; i++ {
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rowID := itr.rowIDs[i]
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columnID := itr.columnIDs[i]
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if (bseek == rowID && pseek <= columnID) || bseek < rowID {
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itr.i = i
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return
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}
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}
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// Seek to the end of the slice if all values are less than seek pair.
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itr.i = itr.n
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}
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// Next returns the next row/column ID pair.
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func (itr *sliceIterator) Next() (rowID, columnID uint64, eof bool) {
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if itr.i >= itr.n {
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return 0, 0, true
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}
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rowID = itr.rowIDs[itr.i]
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columnID = itr.columnIDs[itr.i]
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itr.i++
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return rowID, columnID, false
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}
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